Geometrical instrument



Feb. 27, 1934.

A. o. WALLERIUS 1,948,952

GEOMETRICAL INSTRUMENT Filed March 22, 1932 3 Sheets-Sheet 1 Inventor 1%62 flWaZZerz'zas,

By gamma/51 Feb. 27, 1934.

A. O. WALLERIUS GEOMETRICAL INSTRUMENT Filed March 22, 1932 3 Sheets-Sheet Feb. 27, 1934. A. o. WALLERIUS GEOMETRICAL INSTRUMENT Filed March 22, 1932 3 Sheets-$heet 3 Van v Inventor flfieZfl/VaZZerz'zas,

I flllorney Patented Feb. 27, 1934 FFIQE 2 Claims.

This invention relates to a geometrical instrument, and particularly to an instrument for drawing large circles with a drawing pen or the like; and by use of this device curves can be drawn on a small drawing table corresponding to large circles from three inches to ten feet or over in diameter. The invention, together with its numerous objects and advantages will be best understood from a study of the following description, taken in connection with the accompanying drawings wherein:

Figure l is a side elevational view of the device with the parts arranged ready for use for drawing arcuate lines or circles of a predetermined diameter.

Figure 2 is a similar view showing the use 01 an extension rod when drawing circles or arcuate lines of greater radius.

Figure 3 is a top plan view of the structure shown in Figure 1.

Figure 4 is an elevational view of a combined guide and cap member, an adjusting screw and slide rod associated therewith being shown in cross section.

Figure 5 is a sectional elevational view through a main block, sleeve, center needle pin, and circle revolving block, all being assembled.

Figure 6 is a sectional elevational view showing a slide block and a carpenter's point assembled.

Figure '7 is a transverse sectional view through the center point plate.

Figure 8 is a top plan view of the center point plate.

Figure 9 is a fragmentary elevational view showings. cap member, slide bar, and adjusting screw assembled and more clearly showing the manner of connecting the adjusting screw with the cap member.

Referring more in detail to the drawings it will be seen that 1 indicates a main block which is substantially cylindrical, and which is also provided with an axial opening 2 extending therethrough. A sleeve member 3 is fitted within the opening 2. The sleeve 3 at its upper end is provided with a shoulder 4 arranged to engage in a. recess 5 provided at the upper end of the opening 2.

The upper portion of the main block 1 is reduced to provide an extension 6 and an annular shoulder 7. Immediately adjacent the base of the extension 6 the block 1 is provided with an annular groove 8. A substantially conical hollow revolving block 9 receives the extension 6 and at the base thereoi the block 9 isprovided with an annular rib 10 fitting within the groove 8. Manifestly with the main block 1 and the revolving block 9 connected together as is shown in Figure 5, the block 9 may be revolved relative to the block 1 about the extension 6.

The revolving block 9 at its apex is provided with an integral pin 11. A socket member 12 engages the pin 11, and the socket member- 12 has rising therefrom a pair of spaced parallel ears 13.

A cap member 14 is provided to facilitate rotaticn oi the block 9, and cap member 14 is provided with a reduced and 15 that is pivotally engaged with the ears 13 through the medium of a pivot bolt 16 having a nut suitably engaged therewith.

A slide rod indicated by the reference character 17 is slidable through a slot 18 provided in the cap 14.

An angular arm 19 is secured at one end to the cap 14 and to the free end of the arm 19 there is swivelly connected as at 20 one end of an adjusting screw 21.

A lug member 22 is slidably engaged with the rod 17 and is secured at the desired adjustment relative to the rod through the medium of a set screw 23. The lug 22 is provided with a threaded aperture through which the screw 21 passes, which screw cooperates with the threads of said aperture for shifting a slide rod 17 relative to the cap member 14.

For holding the main block 1 fixed at the center of the circle to be drawn there is provided a center needle pin or shank 24 that is arranged in the bore of the sleeve 3. At its lower end the needle pin 24 is provided with an axial socket accommodating the steel point 25 which is secured at the desired adjustment through the medium of a machine screw 26.

A drawing pen is designated by the reference character 27, and in this particular instance there is provided for the drawing pen a longitudinally split screw or threaded shank 28 to the lower end of which the upper portion of the pin 27 is suitably connected as at 29. Upper and lower nuts 30 and 31 are threadedly engaged with the shank 28 to prevent imdue expansion or distortion of the parallel portions of the shank. Upper and lower lock nuts 32, 33 are also engaged with the shank 28 and in Figure 1 wherein I have shown the shank 28 mounted on the free end of the slide rod 17, it will be seen that said end of the slide rod extends through the slot of the shank, and the upper and lower nuts 32, 33 engage the proximate edges of the rod 17 and thereby serve to lock and secure the screw 28 at the desired vertical adjustment.

The assembly shown in Figure 1 may be used for certain work, the use of such an assembly being thought apparent to those skilled in the art.

There is also provided a slide block designated generally by the reference character 34 and the same includes a tubular shank 35 provided at its lower end with a base or block 36. The bore of the stem or shank 35 is threaded, for threaded reception of the lower end of a longitudinally split screw or threaded shank 37. Lock nuts 38 are engaged with the shank to jam against the upper end of the stem 35 to secure the shank 37 in any desired adjustment. The shank 37 is tubular, and is longitudinally split for use on the outer end of the slide rod 17 in lieu of the shank 28 when the slide block is to be used as will be required for certain work.

In the assembly shown in Figure 2 it will be seen that the rod 1'7 is received through the slot of the shank 37, and the shank is secured at the desired vertical adjustment through the medium of upper and lower nuts 39 and 40 in a manner thought apparent.

For selective use with the slide block 34 there is provided a center point, or as otherwise known in the art a carpenters point 41 which is in the nature of a steel needle provided at its upper end with an enlarged threaded portion 42 for threaded engagement within the bore of the shank or stem 35; and a center point plate 43 which is in the nature of a rimmed disk adapted to receive the lower cylindrical portion of the head 36 of slide'block 34 as suggested in Figure 7. The center point disk or plate 43 is provided at its center with an opening within which is arranged a relatively short tube 44 provided with suitable cross hairs 45. In this connection it will be noted that the head 36 of the slide block is provided at its lower end with a recess 36' to accommodate the upper portion of the tube 44 with the center point plate 33 engaged with the head 36 as shown in the drawings. Manifestly, the center point 41 is used for drawing circles or arcuate lines on rough work such as steel, stone or wood; the center point plate 43, on the otherhand, may be used where a circle is to be drawn without making a hole in the work. Thus the center point plate 43 may be used as many times as desired without perforation of the work whereas: the use of center point 31 several times on the samework might result in perforating or forming holes in thework. As is thought apparent when using the center block 43 the cross hairs 45 are used for accurately positioning the slide block 34 at the point intended to be the center of the circle made or drawn.

When the slide block 34 is used, an additional slide rod 17a is used for connection with the drawing instrument as for example the drawing pen as shown in Figure 2. In this connection, it will be noted, that a split rod 46 is telescoped Within the upper end oi the shank or screw 37 and through the medium or a set screw 47. One end portion of the slide rod 17a is passed through the slot or slit of the shank 46 and opposite portions of the shank are drawn into engagement with the rod 1711 through the medium of a screw 48 engaged with said opposite portions of the shank 46. A cap 49 is threadedly engaged with the upper end of the rod or shank 46. The cap 49 also serves to contract the vertically adjustable shank 46 above the slide rod 1'7 whereby the latter is secured at the desired adjustment.

The shank 28 receives the free end of the rod 17a in the slit of the shank adjacent the upper end, the rod 17a being clamped between the upper nut 30 and the upper lock nut 32 for securing the shank at the desired adjustment.

By use of the assembly shown in Figure 2, and With the main block properly positioned, and the slide block 34 properly adjusted relative thereto, and the drawing pen 27 properly adjusted relative to the slide block 34 the instrument is ready for use and may be properly manipulated for drawing a curved or irregular line as found desirable and in a manner thought apparent to those skilled in the art.

Obviously any number of bars 17, 17a may be used with either of the combinations shown in Figures 1 and 2. When a number of bars, for example the bars 17 are used these bars may be joined together through the medium of relatively short split bolts adapted to accommodate the proximate ends of a pair of such bars, and provided with upper and lower clamping nuts to insure positive engagement of the bolts with the bars, and the retention or the bars in assembled relation.

Having thus described my invention, what I wish to claim as new is:

1. Ina devicefor drawing circles, the combination of a main block and a revoluble block swivelly connected with the main block, a center needle mounted on the main block, a cap mounted on the revoluble block, and having a slot extending therethrough, a bar having an end extending through said slot, co-acting means on said cap and said bar for adjusting said bar laterally relative to said cap, and a marking instrument adjustably mounted on said bar.

2. In a device for drawing circles, in combination, a: main block, a revoluble block swivelly connected with the main block, a centering needle carried by the main block, a bar, means for adjustably mounting said bar on said revoluble block and including meansfor. securing said bar in laterally adjusted position relative to said revoluble block, a base block, a tubular stemrising from said base block, a shank member mounted in a threaded. portion screw threadedly engaged with said stem,said shank member having a slit therethroughreceiving one end ofsaid bar, a second bar, means connecting said second bar with said shank member andincludingmeans for securing said'second bar after the desired lateral adjustment relative to said shank memher, and a marking instrument carried by the second-named bar, and a centerpin carried by said base block.

ABEL O. WALLERIUS. 

